The present invention relates to a lower vehicle-body structure of a vehicle which comprises a side sill which extends in a vehicle longitudinal direction, a center pillar which extends in a vertical direction and is connected to the side sill at a lower end thereof, and a side-sill reinforcement which is provided inside the side sill and has a U-shaped cross section opening toward a vehicle inside.
In the conventional lower vehicle-body structure of a vehicle, the lower end of the center pillar extending in the vertical direction is connected to the side sill extending in the vehicle longitudinal direction. According to this conventional lower vehicle-body structure, in case a load of a vehicle side crash is inputted to the center pillar at the vehicle side crash, the crash load is transmitted to a connection portion of the side sill to the center pillar toward the vehicle inside. Thus, there occurs a case in which the connection portion of the side sill to the center pillar moves toward the vehicle inside, so that the side sill may break.
Accordingly, the lower vehicle-body structure of a vehicle disclosed in US Patent Application Publication No. 2006/0158008A1 has been proposed to solve the above-described problem. That is, as shown in FIG. 25, a side sill 204 having a closed cross section, which comprises a side-sill inner 201, a side-sill reinforcement 202, and a side-sill outer 203, is provided so as to extend in the vehicle longitudinal direction, a lower portion of a center-pillar inner 206 of a center pillar 205 extending in the vehicle vertical direction is connected to a connection portion between the side-sill inner 201 and the side-sill reinforcement 202, a lower portion of a center-pillar reinforcement 207 of the center pillar 205 is connected to the side-sill reinforcement 202, and a center-pillar outer 208 of the center pillar 205 is formed integrally with the side-sill outer 203. Further, the side-sill reinforcement 202 has a U-shaped cross section opening toward the vehicle inside, and a reinforcing member 209 is provided at a lower-outside corner 202a of the side-sill reinforcement 202 to restrain the side sill 204 from bending toward the vehicle inside at the vehicle side crash.
In the above-described conventional structure shown in FIG. 25, the bending of the side sill 204 toward the vehicle inside at the vehicle side crash can be prevented, but there is a problem in that the center pillar 205, in particular, its upper portion inclines so greatly that the center pillar 205 would come toward the vehicle inside as shown by two-dotted lines in FIG. 25. This is because in case the center pillar 205 receives the load of the vehicle side crash, a force to fall down the center pillar toward the vehicle inside may occur, and this force may cause a rotational moment applied to the side sill 204.